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Strategies for finishing of Nellore cattle in grazing

Grant number: 15/02203-1
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): May 01, 2015
Effective date (End): December 31, 2015
Field of knowledge:Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
Principal Investigator:Gustavo Rezende Siqueira
Grantee:Paloma Helena Gonçalves
Home Institution: Departamento de Descentralização do Desenvolvimento (APTA Regional). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil

Abstract

The present study aims the evaluation of nutritional strategies on the termination of Nellore bovines in grazing of Brachiaria brizantha cv. Marandu, in a continuous grazing during the wet season. The experiment will be carried out at the research unit of Polo Regional de Desenvolvimento Tecnológico dos Agronegócios da Alta Mogiana (PRDTA - Alta Mogiana), Colina - SP, Agência Paulista de Tecnologia dos Agronegócios. The experimental period will be conducted from december, 2014 to may, 2015, which will be divided into five periods of 28 days each, in a total of 140 days of experiments. Will be used 78 bovines, uncastrated, Nellore, with initial average weight 409.3 ± 17.8 kg and initial average age of 25 months. From that amount, six will be slaughtered at the beginning of the experiment, in order to estimate the carcass traits and metabolic organs. Moreover, will be utilized 12 Nellore bovines uncastrated and fistulated in the rumen for evaluation of intake and ruminal parameters. The treatments will be as follows: mineral salt, provided 100 g/ animal/ day (control); energetic supplement (7 g/ kg of body weight - BW); mineral salt (first 70 days of experiment) plus high supplementation (20 g /kg of BW) on the last 70 experimental days. The method of grazing used will be continuous stocking, with variable stocking rate. The quantitative and qualitative analysis forage, forage accumulation and animal weighing will be performed every 28 days. In the first half of the 70 experimental days and also in the second half of the last 70 days will be performed evaluations of feeding behavior of the animals, supplement disappearance rate, grazing intake estimative and ruminal parameters (pH, nitrogen amonniacal and short chain fatty acids). The carcass evaluations will be carried out at the beginning and at the end of the experimental period, which will be collected the data of hot and cold carcass weight, yield of hot and cold carcass, losses by cooling, pH, biometric measurements, weight and yield of primary cuts (frontal, flank and special hind quarter), loin eye area and subcutaneous fat thickness in the Longissimus muscle. Experimental design will be evaluated in randomized blocks. The experimental unit adopted will be the paddock, composed by six animals. The data will be analyzed by means of mix model through MIXED proceeding, program SAS, version 9.2.